The present invention relates in general to motor controls, and in particular to a new and useful device for controlling the rotational speed of an electromotor.
A motor control containing a microcomputer is known from German DE-OS No. 28 33 981. The control device contains a digital automatic control system which maintains a preset motor speed. In addition, a counter is provided, which counts the number of oscillator pulses during a clock pulse of a tachogenerator connected to the motor shaft. This number is then taken as the basis of the actual number of revolutions for calculating a revolution number error, compared to the desired revolution number. This revolution number error is then used to correct the motor revolution number.
With the known control, the actual number of revolutions is monitored, whereupon the actual number is registered toward the desired number of revolutions. A revolution number change to large number of desired revolution numbers is not intended.